The invention relates in general to a hose and in particular to a hose for use in bio-pharmaceutical applications.
Pharmaceutical companies typically use hoses to transfer bio-pharmaceutical materials at various locations within the process of manufacturing pharmaceutical products. These bio-pharmaceutical materials may include laboratory and food products as well as various chemicals. A requirement for such hoses is for the inside surface of the innermost layer of the hose (i.e., the surface in contact with the bio-pharmaceutical materials) to be smooth throughout and of a high degree of purity, and thus free from becoming contaminated and/or breaking down (i.e., chemically inert) or degrading relatively quickly over time. Typically the innermost surface of such hoses is required to be sterilized and cleaned relatively frequently, for example, by passing pressurized superheated steam through the hose and/or by an autoclave process. However, such cleaning processes tend to degrade the innermost surface of some prior art hoses over time. Other typical requirements for bio-pharmaceutical hoses include, for example, resistance from permanent kinking, a relatively high degree of flexibility, sufficient hoop strength and tensile strength, relative ease of handling and attachment to mechanical couplings, and a relatively high degree of vacuum resistance (i.e., the resistance to being constricted when negative pressure or suction is applied to the hose).
Prior art hoses for use in the bio-pharmaceutical industry typically comprise a single layer of silicone material or a multi-layered hose having a silicone material for the innermost tubular member. While the silicone material tends to provide moderate levels of flexibility and kink resistance (and, thus, relative ease in handling), the innermost surface of the silicone material nevertheless tends to become contaminated and/or degraded relatively quickly over time, particularly by the repeated steam cleaning process. This results in the replacement of the silicone material hose more frequently than desired. Other prior art bio-pharmaceutical hoses have comprised a layer of a relatively heavy or thick wall of fluoropolymer material where the layer has a relatively smooth innermost surface and a convoluted or spiral-grooved outer surface. However, oftentimes the required smooth finish of the innermost surface of such a hose becomes undesirably compromised over time (e.g., rippled or otherwise deformed), particularly when the hose is flexed. Also, other smoothbore fluoropolymer hoses without a convoluted external outer surface typically lack flexibility and are relatively heavy and thus difficult to handle when the inner diameter of the hose exceeds one inch.
Still other prior art hoses achieve the required level of vacuum resistance through use of a reinforcement layer made of relatively heavy helix wire. However, such a metallic layer tends to be relatively stiff, thereby requiring a large amount of force to flex or bend the hose. Further, when bent, the innermost surface of such a hose tends to lose its smoothness at the point of bending. In other known hoses, the superheated steam vapor used during the steam cleaning process permeates or enters the matrix of the inner wall material. This tends to accelerate the breakdown of the innermost surface of the hose.
What is needed is a bio-pharmaceutical hose having a relatively long-lasting purity of the innermost surface through which the bio-pharmaceutical materials are transferred, while providing a relatively large amount of flexibility and resistance to kinking and steam permeation and also providing relatively high tensile and hoop strength and vacuum resistance, and also being easy to handle and readily attached to mechanical couplings.